Question: $ E = \left[\begin{array}{rrr}2 & -2 & 0 \\ 3 & 0 & 0 \\ -1 & -2 & 0\end{array}\right]$ $ B = \left[\begin{array}{rr}3 & 0 \\ -2 & 1 \\ 0 & 3\end{array}\right]$ Is $ E+ B$ defined?
In order for addition of two matrices to be defined, the matrices must have the same dimensions. If $ E$ is of dimension $( m \times  n)$ and $ B$ is of dimension $( p \times  q)$ , then for their sum to be defined: 1. $ m$ (number of rows in $ E$ ) must equal $ p$ (number of rows in $ B$ ) and 2. $ n$ (number of columns in $ E$ ) must equal $ q$ (number of columns in $ B$ Do $ E$ and $ B$ have the same number of rows? Yes Yes No Yes Do $ E$ and $ B$ have the same number of columns? No Yes No No Since $ E$ has different dimensions $(3\times3)$ from $ B$ $(3\times2)$, $ E+ B$ is not defined.